The performance of PE pipes depends on the quality of the raw materials, processing equipment, and process control. Some manufacturers, seeking profit and cost reduction, even incorporate recycled materials, which directly affects the performance of the pipes. How can you identify quality PE pipes?
1. Appearance
Quality products: The inner and outer surfaces of the pipe are smooth and free of defects such as bubbles, dents, and impurities.
Inferior products: The inner and outer surfaces of the pipe are not smooth, shiny, or free from pitting, or have noticeable dents.
2. Milled Strips
For products made from qualified raw materials, the strips cut by the welder should be bright in color and resist breaking after repeated folding. Milled strips with a whitish or other coloring are caused by the addition of recycled materials or uneven mixing of raw materials. Quality products: Glossy and smooth, they resist breaking after repeated folding.
Inferior products: Dark in color, prone to breaking after folding.
3. Welded Joints:
Qualified welded joints should have smooth, symmetrical flanges along the entire circumference of the pipe, with the minimum flange depth no deeper than the pipe surface. The misalignment at any point on the outer circumference of the weld immediately adjacent to the flange should not exceed 10% of the pipe wall thickness. The flange should be solid and smooth, with a wide base. The underside of the flange should be free of impurities, small holes, distortion, or damage.
High-quality products: The flange is smooth and flat. After the seam is pressurized, the flange can be longer.
Low-quality products: The flange produces numerous pores on the surface. After the seam is pressurized, the flange is short.
4. Smell:
High-quality products: Freshly processed or heated and melted products have a slight plastic aroma, but after cooling, they are odorless.
Low-quality products: They have a pungent odor.
5. Combustion Flame
High-quality products: Burning melt drops are stable, the flame base is light blue, and there is no odor.
Low-quality products: Burning melt drops are unstable, the melt drops are irregular, and there is a small amount of black smoke and odor.
6. Elongation at Break
Elongation at break is the ratio of the length of the specimen at break to its original length. A higher elongation at break indicates greater flexibility and better performance.
High-quality products: Stretched to 3.5 times without breaking.
Low-quality products: Break easily when stretched and have poor toughness.
7. Oxidation Induction Time
The oxidation induction time measures the time it takes for the specimen to begin autocatalytic oxidation under high-temperature oxygen conditions. It is an indicator of a material's resistance to thermal degradation during molding, storage, welding, and use. A longer oxidation induction time indicates better aging resistance and performance.